* ext/nkf/lib/kconv.rb: remove default -m0 and fix document.

          * ext/nkf/nkf-8/{nkf.c, config.h, utf8tbl.c, utf8tbl.h}:
            imported nkf 2.0.7.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@10332 b2dd03c8-39d4-4d8f-98ff-823fe69b080e